Situated at the meeting point of the Yellow River, the Huai River and the Grand Canal of China, the Qingkou complex is a large comprehensive water conservancy project built from the sixteenth to nineteenth centuries to solve the problems for the Grand Canal to join the Huai River and cross the Yellow River. Through the World Cultural Heritage nomination of the Grand Canal, the composition, operation mechanism and evolution of Qingkou complex is comprehensively studied. This paper summarises these findings, and maps a complete view of the Qingkou complex - an engineering masterpiece along the Grand Canal of China.